Chopper-Based Real-Time Load Emulator with Feed-Forward and Hysteresis Current Controller

Nowadays, the usage of load emulators, is the best method for implementation and analysis of different electrical load change scenarios in laboratories. This paper presents an improved programmable load emulator which can emulate both reference active and reactive power simultaneously. The proposed control system can track the dynamic load changes rapidly and accurately in addition to pulse change emulation. So it is completely suitable for both dynamic and transient stability analysis. The emulator topology is made up of an inverter and a buck converter. Simple PI controller because of its coefficients dependence to operating point is not suitable especially for this application in which the operating point is constantly changing in a wide range. The usage of a Feed-Forward controller for grid side inverter increases the DC bus voltage stability and on the other hand the usage of the hysteresis current controller for buck converter improves the rate and accuracy of the reference active power tracking. Simulation results in SIMULINK verify the performance of the proposed control system.